Stop mechanism particularly for straight bar knitting machines



(5. WILDERS EI'AL Nov. 23, 1943.

STOP MECHANISM PARTICULARLY FOR STRAIGHT BAR KNITTING MACHINES Filed Oct. 2'. 1942 2 Sheets-Sheet 1 flllIll lllllllllllllllIIIHIHIIH Hlll IIIIH IIHIIIHHIH HHIIHI' Nov. 23, 1943'.

G. WILDERS ETAL 2,335,095 STOP MECHANISM PARTICULARLY F OR STRAIGHT BAR KNITTING MACHINES Filed Oct. 2, 1942 2 Sheets-Sheet 2 I //v1 /vm 4 G'c arr 1 il e'ldens' nd Wm. Gj lacdana Id;

Patented Nov. 23, 1943 PARTICULARLY FOR STRAIGHT BAR KNITTING MACHINES George Wilders, Kegworth, and William Gordon Macdonald, Loughborough, England, assignors to William Cotton Limited, Loughborough,

STOP MECHANISM England Application October 2, 1942, Serial No. 460,558 In Great Britain October 11, 1941 6 Claims. (CI. 66-82) This invention is concerned with Cottons patent and other straight bar knitting machines, and is primarily but not exclusively concerned with the single section type of Cottons patent knitting machine that has recently been evolved for knitting the heel tabs on to stocking blanks. In this machine the cam shaft is driven through a pinion mounted on and adapted to be shogged with such shaft. The male part of a dog clutch is associated with this pinion, and the female part of this clutch is mounted on or associated with the draw cam which is itself freely mounted on the shaft; when the shaft and pinion are shogged the dog clutch is engaged or disengaged according to the direction of shogging to couple the cam to or to uncouple it from the driving pinion. In order that the draw cam may be brought to a standstill, when it is uncoupled, a friction brake is associated therewith, but it has been found that this friction brake is not of itself sumcient to ensure that the draw cam always stops in the same position so that the thread carriers are located beyond the selvedge needles; variation in the angular position reached by the draw cam when it is brought to a standstill will result in the carriers being located inwards of the selvedge needles, so as to interfere with the operation of the transfer points.

The main object of the present invention is to provide simple and efiicacious alternative means for achieving this result and with this and other objects in view the invention consists in a Cottons patent or other straight bar knitting machine wherein the draw mechanism is capable of being disconnected from its driving means and there is provided a friction brake for bringing the disconnected draw mechanism to rest and positive locking means for locking the draw mechanism in a predetermined position of rest, characterised in that the positive locking means comprises a projection on a rotating part of the draw mechanism and a. slidable member restrained against rotation with said rotating part but slidably movable into the path of rotation of the projection.

Conveniently but not necessarily the rotating part is constituted by the cam and the projecting part projects from the side of such cam. Alternatively the projecting part projects from the side of a disc co-axially with the cam.

The foregoing and other features of the invention set out in the appended claims are incorporated in the constructions (suitable for application to a heeling machine for the purpose of ensuring the arrest of the carriers beyond the selvedges) shown in the accompanying drawings, in which:

Figures 1 and 2 are, respectively, an end elevation and a plan of one construction, and

Figures 3 and 4 are, respectively, an end elevation and a plan of another construction.

According to one method of carrying the invention into effect as applied to single section machines of the type referred to, a bell crank lever l0 pivoted to the machine frame at H has a roller l2 on one arm in rubbing contact with one side face of the pinion l3 and its other arm is connected by a spring Hi to a yoke Hi the ends of which carry an arcuate brake shoe l6 coaxial with and normally displaced a short distance from the periphery of the disc cam H which may be attached to or formed integrally with the draw cam not shown; or may be mounted on the cam shaft 21 to rotate with the draw cam. This brake is conveniently of the same width as the disc and depending radially from one edge of the brake towards the disc centre is a tongue l8 so that when the pinion I3 is shogged to disengage the dog clutch IS the bell crank lever If! is pivoted to apply the brake and the said tongue l8 moved towards the disc centre. When the brake is off, the tongue I3 is disposed beyond the periphery of the'disc H but when the brake is applied the tongue is moved so that part of it lies inside the periphery, preferably flush with one side face of the disc and when in this position the tongue co-acts with a projection 20 formed on such side face. This projection 20 is conveniently of arcuate configuration and is fixed by screws and extends from the periphery towards the-.disc centre for a short distance, the

' arrangement being such that after the brake has been applied the projection 2i! rotating-with the .disc [7, in the direction of the arrow in Fig. 1

abuts against the tongue l8 and the disc is thus 'alway's stopped in the same position. The aforesaid spring I l connecting the yoke 15 to one end of the cranked lever Ii] is preferably a coil spring and disposed axially within it is-a rod 2| of such a length that the spring is always under tension the arrangement being such that when the pinion i3 is shogged to re-engage the clutch I9 the return movement of the lever in under the action of such spring I4, is arrested by such rod 2| immediately prior to the final engaging movement of the clutch the release movement of the brake i6 and yoke l5 being effected by two compression springs 22 each surrounding a short guiding rod 23 (the two rods being parallelly disposed) extending from a fixed part 24 and projecting through bosses l5 formed integral with said yoke l5. Said bosses are mounted for sliding movement on said rods 23 and the compression springs 22 are located between the bosses l5 and the fixed part 24 from which the rods 23 extend. The arrangement is such that thebrake shoe 1 6 is moved to the off position and the tongue I8 is moved out of the path of the projection before the clutch l9 re-engages. In an alternative con-' struction the springs for moving the .brake shoe and associated tongue to an inoperativeposition are dispensed with and positive means for effecting such movement are provided.

In a preferred method (Figs. 3 aud t) of carry.- ing the invention into eifectthe brake mechanism is as described with reference to the first embodiment but the tongue 18 adapted to cooperate with the projection 20 for positively stopping the draw cam always in the same .position is carried by a sleeve slidably mounted on a pin .26 extending "from :themachine frame, the axis of such pin 26 being parallel with the axis of the cam shaft 2"! on which the pinion i3 is fixedly mounted, and :on which the .draw cam and the disc I] are rotatablymounted. The axis of the pin :26 is outside the periphery of the pinion I13 and disc H, and a fork .28 on thesleeve .25 engages the two side faces of the pinion 13 so that as the pinion i3 is shogged in either direction the sleeve 25 is similarly shogged relatively the pin '25. A fixed guiding pin '29 is provided to prevent rotation of the sleeve. When the clutch I9 is engaged the tongue I'B occupies a. position, "beyond that face of the disc I "I on which the projection 20 is mounted, out of the path of movement of such projection. When the pinion 1:3 is .shogged to disengage the clutch IS the :brake is applied by the cranked lever in as before-described and the tongue I8 is moved towards such face of the disc :l'! into the path of movement of the projection 20 and thereby ensures that the cam is always stopped the same position. If .desired there may be two spaced projections on the disc and the tongue may be moved to occupy a position between and abutting against the opposed ends of such pro- J'ections so that it inhibits movement of the cam in either direction and thereby prevents rebound. This latter arrangement is not, however, normally to be recommended. One .of the main uses of the mechanism is to ensure that the thread carrier actuated through the instrumentality of the draw cam shall always stop at the end of its traverse for if the cam continues to rotate after the carriage has reached the end of its traverse the carrier commences its return motion with the result that the end needles of the selvedge are pressed off. In general, the pinion is will be shogged by shogging the cam shaft 2'5,

The positive stop mechanism described herein ensures that the carrier is stopped at the end of its traverse even though, as is usually the case with heeling machines of the type referred to, the carriers are run at comparatively high speeds and even though the brake shoe may become Worn or its efficiency impaired by oil or grease. Nevertheless a small amount of rebound is not detrimental (that is to say the amount of rebound is such that the carrier Will still be beyond the selvedge needle) and a feature of both types of stop mechanism described herein particularly when used with fast running machines is that consequent upon a small measure of rebound being permitted the mechanism is if the cam is of dished formation may be constituted by a radial rib; in this event the inner end .of the tongue is provided with an inwardly directed right-angled projection for engaging said rib.

Whilst the invention has been described with particular reference to fast running straight bar knitting machines for knitting heels it will readily be appreciated that it may with advantage be applied to numerous other types of machines andfor numerous difierent purposes.

We claim:

1. Inja straight barknitting machineof the kind having draw mechanism capable of being disconnected from its driving means and a friction brake for bringing the disconnected draw mechanism to rest; the combination with a ro- .tatable part of the draw mechanism, of positive locking means for locking the draw mechanism in a predetermined position of rest, comprising a projection on said rotating part, a slidable member movable into and out of the path of the projection, mean restraining the said member against rotation with said projection,'and means for moving the said member into said path when the draw mechanism is disconnected.

2. A knitting machine according to claim 1, having the slidable member movable radially into and out of the path of the rotatable projection.

3. A knitting machine according to claim 1, having the slidable member movable axially into and out of the path of the rotatable projection.

4. In a straight bar knitting machine of the kind having draw mechanism capable of being disconnected from its driving means and a friction brake for bringing the disconnected draw mechanism to rest; the combination of a rotatable brake disc having a periphery for engagement by the friction brake, a projection on a side of said disc, a slidable member movable radially into and out of the path of the projection, means restraining the said member against rotation with said projection, and means for moving the said member into said path when the draw mechanism is disconnected.

5. In a straight bar knitting machine of the kind having draw mechanism capable of being disconnected from its driving means and a friction brake for bringing the disconnected draw mechanism to rest; the combination of a rotatable brake disc having a periphery for engagement by the friction brake, a projection on a side of said disc, a fixed axially-extending pin, a sleeve slidable thereon, a part on the sleeve movable by said sliding movement into and out of the path of the projection, and means for moving the sleeve to bring said part into said path upon application of the friction brake.

6. In a straight bar knitting machine having a shogging cam shaft and draw mechanism capable of being disconnected from it driving means, the combination of a driving pinion fast on the cam shaft, a draw cam on the cam shaft, a dog clutch for driving the draw cam from the pinion and comprising two dog members, separable by shogging the cam shaft to disconnect the draw cam from its drive, whereof one memher is connected to the draw cam and the other to the pinion, a brake disc rotatable with the draw cam, a friction brake for engaging the periphery of the brake disc, a projection on a side face of the brake disc, a member slidabie into and out of the path of rotation of said projection, and connections for applying the friction brake and for moving the last said member into the path of the projection when the pinion is shogged to disengage the dog clutch, whereof the connections for applying the brake comprise springs for resiliently transmitting the brake applying effort.

GEORGE WILDERS. WILLIAM GORDON MACDONALD. 

